We're sorry to hear about the high volume of harassing calls you're receiving. The calls you're describing are spoofed calls. Spoofing is a tactic that spam callers use to change their number to display any number they'd like. Unfortunately, there is no service out there that is able to identify and block spoofed calls. We've done our best to combat these calls by blocking any calls with the same first 5 to 6 digits as your number.
If the calls are not coming from your area code followed by the next 2 to 3 numbers, then you can manually add the area code + next 2 numbers that are bothering you into your RoboKiller block list using our WildCard Blocking feature.
For more information on how to use our WildCard Blocking feature see this other Help Center Article - https://support.robokiller.com/hc/en-us/articles/360026784932-How-do-I-block-wildcard-patterns-on-my-iPhone-